This paper describes a repeated plus shaped slot fractal antenna .This antenna show multiband behavior due to self similarity in their structure. Proposed Antenna achieves wide bandwidth ranging from 2.20 GHz to 3.51 GHz. This antenna utilized dielectric substrate which has dielectric constant 4.4 and thickness 1.6mm. Proposed antenna show percentages bandwidth 45 and it offer gain 3.05dBi, directivity 3.32dBi and antenna efficiency 93.98% at resonant frequency 2.41 GHz. So this plus shape slot fractal antenna shows various applications for WiMAX/WLAN.

1. IJSRD - International Journal for Scientific Research & Development| Vol. 2, Issue 09, 2014 | ISSN (online): 2321-0613
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Repeated Plus Shape Slot Fractal Antenna For WiMAX/WLAN
Application
Shashank Kumar Gupta1
Rajat Srivastava2
Shahanaz Ayub3
1,2,3
Bundelkhand Institute of Engg & Technology Jhansi Uttarpradesh.
Abstract— This paper describes a repeated plus shaped slot
fractal antenna .This antenna show multiband behavior due
to self similarity in their structure. Proposed Antenna
achieves wide bandwidth ranging from 2.20 GHz to 3.51
GHz. This antenna utilized dielectric substrate which has
dielectric constant 4.4 and thickness 1.6mm. Proposed
antenna show percentages bandwidth 45 and it offer gain
3.05dBi, directivity 3.32dBi and antenna efficiency 93.98%
at resonant frequency 2.41 GHz. So this plus shape slot
fractal antenna shows various applications for
WiMAX/WLAN.
Keywords: Fractal Antenna, Multiband antenna, WLAN,
WiMAX
I. INTRODUCTION
In the field of wireless communication micro strip
patchAntenna plays a vital role. Micro strip patch antenna
show various advantages for low profile communication
system like low cost, low weight, flexibility and ease of
integration with active devices. For monolithic microwave
integrated circuit micro strip patch antenna show a good
solution.
Micro strip patch antenna show some limitation
like low bandwidth, low gain and it cannot process
multiband .so for overcome this limitation many type of
miniaturization technique ,like utilizing high dielectric
substrate , applying reactive and resistive load and
increasing the electrical length of antenna have been
proposed and utilized .
Fractal geometry of antenna is a good solution for
obtain better bandwidth result. Fractal geometry patch
structure increases its effective electrical length at the same
time reducing their overall geometrical size. Fractal antenna
shows feature that it has a self similar structure and space
filling properties. Fractal shaped structure has various
advantages like multi band, wide bandwidth and reduced
antenna size. Fractal antenna uses a self –similar design to
maximize the length or increase the parameter on inside
sections or the outer structure of material that can receive or
transmit electromagnetic radiation within a given total
surface area or volume[1].
In the present work, a plus shape patch is taken as a
base shape and its iteration are placed touching the base
shape.[2]Due this iteration performed the proposed antenna
called as a repeated plus shaped slotted fractal antenna[3].
The substrate material play very important role in deciding
the size and bandwidth of antenna [4]. For given antenna
glass epoxy substrate utilized which has the dielectric
constant 4.4 and the thickness of dielectric is 1.6mm.
II. ANTENNA DESIGN CONSIDERATION
The design of proposed antenna is shown in Fig 1. The
ground plane length and width are taken 38mm and 40mm.
For ground plane we utilized glass epoxy substrate which
has dielectric constant 4.4 and height of plane 1.6mm [5].
The resonant frequency of antenna is 2.41 GHz. For making
plus shape slotted patch we utilizing square patch which has
side 2mm [6]. Line feed technique is used for feeding the
antenna [7]. Line feed has length 2mm and width 13mm.
Fig. 1: Geometry of proposed plus shape slotted fractal
Antenna.
Table 1 shown all specification for designing of plus shape
slot fractal antenna.
S.N. Parameters Value
1. Design resonance frequency 2.41GHz
2. Dielectric constant 4.4
3. Substrate height 1.6mm
4. Ground plane length 38mm
5. Ground plane width 40mm
6. Side of square patch 2mm
Table 1: Antenna parameter specification
III. SIMULATION RESULT AND DISCUSSION
Plus shape slot fractal antenna for WiMAX/WLAN
application simulated and analyzed by using IE3D software
version 9.0 which is resonated at frequency 2.41 GHz . The
percentage bandwidth of fractal antenna is 45 % and the
antenna efficiency of proposed antenna is found to be
93.98%. The proposed antenna offer gain 3.05dBi and
directivity 3.32 dBi .VSWR of proposed fractal antenna is in
between 1 and 2 over entire frequency band.
Fig 3 to 8 shown different characteristic of plus
shape slotted fractal antenna.

2. Repeated Plus Shape Slot Fractal Antenna For WiMAX/WLAN Application
(IJSRD/Vol. 2/Issue 09/2014/073)
All rights reserved by www.ijsrd.com 329
Fig. 2: shown the graph of resonant frequency of
plus shape slotted fractal antenna. Resonant frequency in
graph is 2.41GHz.Frequency band of antenna 2.2GHz to
3.51GHz.
Fig. 3: shown the radiation pattern of fractal antenna
Fig. 4: shown the graph of radiation pattern of fractal
antenna. VSWR of proposed fractal antenna is in between1
and 2 over entire frequency band which shown in fig.
Fig. 5: shown the 2-d polar plot of plus shape slot fractal
antenna. Fig shown Bi -directional radian pattern.
Fig. 6: shown the efficiency vs. frequency graph the antenna
efficiency of fractal antenna is 93.98% at resonate frequency
2.41 GHz.
Fig. 7: shown the smith chart of fractal antenna
Fig. 8: shown the gain vs. frequency graph .Gain of antenna
found 3.05dBi at resonate frequency 2.41 GHz.

3. Repeated Plus Shape Slot Fractal Antenna For WiMAX/WLAN Application
(IJSRD/Vol. 2/Issue 09/2014/073)
All rights reserved by www.ijsrd.com 330
IV. CONCLUSION
The characteristic of proposed fractal antenna studied
through by IE3D simulation software. It is found that
proposed repeated plus shape slot fractal antenna shows
very high antenna efficiency which is equal to 93.98% and
antenna cover the frequency range of 2.2GHz to 3.51GHz
which is suitable for WLAN/WiMAX application[8-10]. It
is found that fractal antenna provides much better result than
simple patch antenna
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